Single lens panoramic camera

ABSTRACT

Apparatus for enabling a panoramic camera to make a plurality of scans of an area of interest during each revolution of the scanning mechanism, including deflection means for scanning the area of interest and means for moving the deflection means relative to an axis transverse to the axis of rotation of the scanning mechanism after a scan has been completed during a first portion of a revolution, to reorient the deflection means to perform another scan of the area of interest during another portion of that revolution.

sewers sit United States a Joseph F. G. Miller Lincoln, Mass.

Apr. 15, 1968 Feb. 16, 1971 ltek Corporation Lexington, Mass.

a corporation of Delaware [72] Inventor [21 Appl. No. [22] Filed [45}Patented [73] Assignee [54] SINGLE LENS PANORAMIC CAMERA 14 Claims, 3Drawing Figs.

52 us. Cl

EAS

T @ZON NORTH DIRECTION OF FLIGHT PATH 95/16, 95/125 [51 1 Int. Cl G03b37/02 [50] Field ot'Search ..95/l 2.5, 15, 16, 17

[56] References Cited UNlTED STATES PATENTS 2,955,518 10/1960 Perry95/125 3,023,662 3/1962 Hicks 95/16X Primary ExaminerJohn M. HoranAttorneys-Homer 0. Blair, Robert L. Nathans, Lester S.

Grodberg and Joseph S. landiorio ABSTRACT: Apparatus for enabling apanoramic camera to make a plurality of scans of an area of interestduring each revolution of the scanning mechanism, including deflectionmeans for scanning the area of interest and means for moving thedeflection means relative to an axis transverse to the axis of rotationof the scanning mechanism after a scan has been completed during a firstportion of a revolution, to reorient the deflection means to performanother scan of the area of interest during another portion of thatrevolution.

SEARCH R00;

PATENTEU FEB] BIS?! 3563; 146

sum 1 OF 2 NORTH DIRECTION OF FLlGHT PATH g 12 29' WEST HORiZON JOSEPHF. a. MILLER INVENTOR.

FIG. 2. JMM

ATTORNEY SINGLE LENS PANORAMIC CAMERA CHARACTERIZATION OF INVENTION Theinvention is characterized in apparatus in a panoramic camera having ascanning mechanism for providing a plurality of scans of an area ofinterest during each revolution of the scanning mechanism comprisingfirst deflection means for scanning the area of interest and first meansfor moving the deflection means relative to an axis transverse to theaxis of rotation of the scanning mechanism after a scan has beencompleted during a first portion of a revolution to reorient the firstdeflection means to perform another scan of the area of interest duringanother portion of that revolution.

BACKGROUND OF INVENTION This invention relates to panoramic cameras and,more particularly, to such cameras capable of continuous scanning usinga single lens system.

Generally, in panoramic cameras full cycle scanning is accomplished bymeans of two lens systems which are offset from one another, for exampleby l08. Thus after one system completes its scan of the ground during afirst part of a revolution of the scanning mechanism and is beingrecycled, the other lens system is scanning the area of interest.

Although such double lens systems provide the capability for full cyclescanning, they increase the cost, the weight, the size. and thecomplexity of the equipment as compared to a single lens panoramiccamera.

SUMMARY OF INVENTION Thus it is desirable to have available a panoramiccamera having a single lens system scanning mechanism capable of fullcycle scanning of the area of interest.

The invention may be accomplished by a panoramic camera having arotatable support member, drive means for rotating the support member none direction, and first and second radiation reflective elementsmounted for rotation with the support member. The first radiationreflective element scans the area to be photographed from a firstangular limit to a second angular limit in the direction of rotation anddirects the radiation from that area along the support member to thesecond radiation reflective member which directs the radiation onto aphotographic film. The first reflective element is movable relative toan axis transverse to the rotational axis of the support member. Meansare provided for moving the first reflection means relative to thattransverse axis after it has completed scanning from the first to thesecond limit, to position the first reflection means to again receiveradiation from the direction of the first limit and direct it along thesupport member to the second reflection means.

DISCLOSURE OF PREFERRED EMBODIMENTS Other objects. features andadvantages will appear from the following description of preferredembodiments, taken with the accompanying drawings, in which:

FIG. I is a diagrammatic perspective view of a portion of a panoramiccamera utilizing two mirrors mounted at either end ofa rotatable member,photographic film held in a cylindrical path by a platen, and means forrotating each of the mirrors about an axis transverse to the rotationalaxis of the rotatable member according to this invention;

FIG. 2 is a view of a portion of FIG. I with parts removed and inperspective showing alternate means to move the mirrors relative to atransverse axis;

FIG. 3 is a diagrammatic perspective view of a portion of a panoramiccamera similar to FIG. I in which the second, or imaging, mirror is notrotatable about an axis transverse to the rotational axis of therotatable member and the platen holds the film in a cylindrical pathwhich is substantially a closed path about the rotatable member. Aportion of a single lens embodiment of the invention capable of fullcycle scanning is shown in FIG. 1, where the vehicle carrying the camerais shown by arrow 12 to be on a northerly course. The camera in FIG. 1is the optical bar type and includes scanning reflector element 14,imaging reflector element 16 and lens 18. which may be a lens system ofthe G'aus or Triplett type, housed in support member 20 and rotated bymotor 22 about longitudinal axis 24 in the counterclockwise direction,arrow 26. Thus, scanning of the ground takes place from east to west byreflecting surface or mirror 28 of reflecting element 14 and the imageis projected onto film 30, disposed in platen 32 in a cylindrical pathconcentric with longitudinal axis 24, from west to east by reflectingsurface or mirror 34 of reflecting element 16. As member 20 rotatesmirror 28 scans the ground through axial slit 29 and reflects thelighttherefrom to mirror 34 in a path coincident with longitudinal axis 24and through lens 18. The light is then reflected again by mirror 34through axial slit 35 and imaged on film 32 above so that narrowsections of the film transverse to the scan direction are successivelyexposed. The optical axis of mirrors 28 and 34 and lens 18 need not becoincident with the axis 24 of rotation of member 20, nor even parallelto it: it may be skew to axis 24. Film 30 passes over roller 36 throughplaten 32 and over roller 38 rotated at constant uniform speed by motor40 to drive film 30 in the direction of arrow 42.

At the beginning of a scan mirror 28 faces toward the east limit orhorizon and mirror 34 faces toward the west limit or horizon, i.e. thearea proximate roller 38. As member 20 rotates, mirror 28 scans acrossthe ground from east to west horizon or limit while mirror 34 sweepsacross film 30 from the area of the film near roller 38 to the area ofthe film near roller 36, i.e. from west to east. In FIG. 1 member 20 isshown at the midway point of its rotation from east to west whereinmirror 28 is facing approximately. straight down at the ground andmirror 34 is facing straight up at the center of film 30.

When mirror 28 is facing the west horizon it is no longer scanning areasof interest on the ground but is scanning the sky or a portion of thecamera housing, and mirror 34 is no longer directed at photographic film30 but onto a portion of the camera housing. In conventional panoramiccameras this problem may be solved by using a second lens system whichis offset 180 from the first system, so that as one lens system losessight of the ground and sees the sky or camera housing the other lenssystem is leaving the camera housing and beginning to see the ground.

The present invention solves the problem without addition of a secondlens system by means of elements 14 and 16 mounted on shafts 44 and 46which are transverse to the axis of rotation of member 20 and rotatableby motors 48 and 50, respectively. When mirror 28 is facing toward thewest and mirror 34 is facing toward the east at roller 36 or off thefilm completely, motors 48 and 50 are energized to rotate shafts 44 and46 in the counterclockwise direction, arrows 52. A 90 counterclockwiserotation of each element repositions it transverse to its previousposition so that when scanning begins the second time at the easthorizon mirrors 28 and 34 assume the orientation previously held whenscanning began at the east horizon the first time. Thus, although member20 has rotated only half a revolution, the mirrors are again recordingas when member 20 was at the beginning of the revolution or as if member20 had already rotated at full revolution. Mirrors 28 and 34 are nowoperative through slits 29' and 35', respectively. The 90 rotation ofelements 14 and 16 about shafts 44 and 46, respectively, is repeatedafter each scan.

It should be understood that a scan in which the limits are oppositehorizons might not be and generally is not a 180 scan but some angleless than 180, for example I40". Then. establishing 0 and 180 as beingthe directions straight out from the sides of the camera and airplane,the scan would begin at 20 and end at while the sweep of the film wouldbegin at 200 and end at 340. Thus, when one mirror reaches the end ofscan, l60 limit, and the other reaches the end of film sweep, 340 limit,they need not be rotated immediately; they may be rotated any timeduring the period that the optical bar is rotating the interim 40, untilthe time when those minors reach the 200 and 20 limits, respectively.Rotation precisely at 160 and 340 directs the mirrors back toward the 20and 200 limits, i.e. in that general direction, but not right at themuntil the optical bar rotates that interim 40. In this manner a singlelens system comprising lens 18 and mirrors 28 and 34 may providefulltime scanning.

Instead of having reflecting element 14 mounted on shaft 44 for rotationby motor 48, a linear actuator 54, FIG. 2, such as a solenoid, may besubstituted for motor 48, so that mirrors 28 and 34 may be shifted intoand out of the optical axis of lens 18 along an axis transverse to thelongitudinal axis 24. For example, two reflecting elements 58, 60 may bepositioned adjacent each other on shaft 62 offset 90 from each other.Then when the reflecting element performing the scanning operation canno longer scan the ground, the solenoid would be energized to move itsshaft and shift the other reflecting element into scanning position. Andreflecting element 16 may also be controlled in this manner.

Certain structures have been included here for ease of understanding butare not essential to the inventive concept. For example, the camera neednot operate with visible light but may as well perform with ultraviolet,infrared, X-ray, and other forms of radiation; the translating systemfor focusing the radiation need not be an optical lens system 18. Theterm photography or photographic is used here in its fullest sense, viz.the art or process of producing images on a sensitized surface by theaction of light or other radiant energy. The invention is not limited touse with mirrors or other reflective elements for refractive elementsmay also be used to deflect the radiation. In addition, the invention isapplicable in cameras performing oblique scans. I

Another embodiment of this invention capable of scanning with a singlelens system scanning mechanism is shown in FIG. 3; like parts have beengiven like numbers accompanied by a prime mark. The primary structuraldistinction between the embodiments of FIGS. 1 and 3 is that in theembodiment of FIG. 3 reflecting element 16' is not movable relative toan axis transverse to the axis of rotation of member 20. Film 30' isdisposed in a cylindrical path about member 20 in substantially a closedpath in order to provide a recording medium for mirror 34' as it rotateswith member 20'.

Film 30' is fed around roller 36' and over cylindrical platen 32' in thedirection shown by arrow 42 by drive roller 38' driven by motor 40'.Alternatively, two film supplies may be used to feed two film segments30, 30" through two semicircular platens, in which case film 30' wouldbe drawn around roller 36' and through the platen by drive roller 38',and film 30" would be drawn in the direction of arrow 42" around roller38 and through the platen by roller 36" driven by another motor similarto motor 40 or by motor 40 by means of a suitable transmission. Or film30" may be drawn in the direction of arrow 42', around roller 36" andthrough the platen by roller 38" driven by a motor not shown. As member20' rotates continuously at uniform speed element 16' is notrepositioned relative to member 20' twice in each revolution. Rather,mirror 34 of element l6 remains stationary through a full rotation 360.Mirror 28 is operative through slits 29" and 29' (not visible becauseofcutaway view) and mirror 34' is operative through slit 35".

In the embodiment of FIG. 3, if the film is fed as two separate films30' and 30", and film 30' is driven in the direction of arrow 42' whilefilm30" is driven in the direction of arrow 42", the films may be drivenwith continuous uniform motion. But a different result is obtained ifthe film in the lower portion of the platen is moving in the directionof arrow 42" whether the film in the upper and lower portions is onecontinuous length or two separate lengths. For then film in the lowerportion is moving in the same direction as the image is, as the image isswept across the film by the rotating mirror 34'. This relationship maybe expressed:

where V, is the scan speed of the image at the film, V, is the speed ofthe film and V, is the speed of the image relative to the film. In theupper half of platen 32' the film is moving in the opposite direction tothe image as it is being swept across the film by mirror 34 and thisrelationship is expressed:

Thus when the image is being swept across film in the upper half ofplaten 32 the speed of the film V; is equal to the difference betweenthe image speed V, and scan speed of the image at the film V requiredfor operation of the optical bar camera. However when the image is beingswept across the film in the lower half of platen 32' the speed of thefilm V,- is equal to the sum of the image speed V, and scan speed of theimage at the film V required for operation of the optical bar camera. Asa result during portions of the scan utilizing the lower half of thefilm, the film must be moved 2V twice the scan speed of the image at thefilm, faster than when the film in the upper half is utilized, in orderto maintain the proper relative motion between the image and film in theoptical bar camera.

As is apparent from the foregoing explanation of two specificembodiments, the invention may take many forms. Other embodiments willoccur to those skilled in the art and are within the following claims.

lclaim:

l. A panoramic camera having a single lens system scanning mechanism,which rotates about an axis of rotation, for providing a plurality ofscans of an area ofinterest during each revolution of said scanningmechanism, comprising:

a. said scanning mechanism having first deflection means for scanningthe area of interest, and first means for moving said deflection meansrelative to an axis transverse to the axis of rotation of said scanningmechanism after a scan has been completed during a first portion ofrevolution to reorient said deflection means to perform another scan ofthe area of interest-during another portion of that revolution; and

b. said scanning mechanism further having second deflection means spacedfrom said first deflection means for rotation with said first deflectionmeans, and second means for moving said second deflection means relativeto an axis transverse to said axis of rotation after said firstdeflection means has completed scanning from a first and second angularlimit and said second deflection means has exposed a section of filmbetween a third and a fourth angular limit, to position said seconddeflection means to receive radiation from saidv first deflection meansand again direct it toward said third angular limit.

2. The panoramic camera of claim I in which said second means for movingincludes shaft means parallel to said transverse axis relative to whichsaid second deflection means is movable, and to which said seconddeflection means is fixed, and second drive means for moving said shaftmeans.

3. The panoramic camera of claim 2 in which said second drive meansimparts rotational motion to saidshaft means.

4. The panoramic camera of claim 2 in which said second drive meansimparts linear motion to said shaft means.

5. A panoramic camera having a single lens scanning mechanism forproviding a plurality of scans of an area of interest during eachrevolution of said scanning mechanism comprising:

first radiation reflection means for scanning an area to be photographedfrom a first angular limit to a second angular limit;

film positioning means for receiving photographic film and supporting itin a cylindrical path around the axis of rotation ofsaid scanningmechanism;

second radiation reflection means, spaced from said first reflectionmeans and rotatable with it, for receiving radiation from said firstreflection means and directing it onto 3 said film from a third to afourth angular limit;

means for moving said first reflection means relative to an axistransverse to said axis of rotation, after it has completed scanningfrom said first to said second limit, to position said first reflectionmeans to again receive radiation form the direction of said first limitand reflect it to said second reflection means; and

second means for moving said second reflection means relative to an axistransverse to said axis of rotation, after it has completed directingradiation onto said film between said third and fourth limits, to againdirect radiation from said first reflection means toward said thirdlimit.

6. A panoramic camera having a single lens system scanning mechanism,which rotates about an axis of rotation, for providing a plurality ofscans of an area of interest during each revolution of said scanningmechanism, comprising:

a. film positioning for receiving photographic film and positioning itin a plurality of arcuate portions ofa cylindrical path around said axisof rotation; and

b. said scanning means having first deflection means for scanning thearea of interest, and first means for moving said deflection meansrelative to an axis transverse to the axis of rotation of said scanningmechanism after a scan has been completed during a first portion of arevolution to reorient said first deflection means to perform anotherscan of the area ofinterest during another portion of that revolution.

7. A panoramic camera having a single lens system scanning mechanismwhich rotates about an axis of rotation, for providing a plurality ofscans of an area of interest during each revolution of said scanningmechanism, comprising:

a. film positioning means for receiving two photographic films andpositioning each ofthem in separate arcuate portions of a cylindricalpath around said axis of rotation; and

b. said scanning mechanism having first deflection means for scanningthe area of interest, and first means for moving said deflection meansrelative to an axis transverse to the axis of rotation of said scanningmechanism after a scan has been completed during a first portion of arevolution to reorient said first deflection means to preform anotherscan of the area of interest during another portion of that revolution.

8. A panoramic camera having a single lens system scanning mechanism,which rotates about an axis of rotation, for providing a plurality ofscans of an area of interest during each revolution of said scanningmechanism, comprising:

said scanning mechanism having first deflection means for scanning thearea of interest, and first means for moving said deflection meansrelative to an axis transverse to the axis of rotation of said scanningmechanism after a scan has been completed during a first portion of arevolution to reorient said first deflection means to perform anotherscan of the area of interest during another portion of that revolution;and

b. said scanning mechanism further having second deflection means,including a reflection element, spaced from said first deflection meansfor rotation with said first deflection means. 7

9. In an optical bar panoramic camera wherein an optical bar scanningmechanism with a single lens system rotates about a scanning axis toscan a film medium, positioned in a cylindrical plane about the scanningaxis, with the image of a photographed scene, the improvement comprisingdeflection means, including a positionable image deflector, in saidscanning mechanism for deflecting said image to the film medium by afirst optical path, havin a first entrance aperture, during a firstscanning period w en said first entrance aperture faces said scene andsaid image deflector is in a first position, and for deflecting saidimage to the film medium by a second optical path, having a secondentrance aperture, during a second scanning period when said secondentrance aperture faces said scene and said image deflector is in asecond position, said first and second entrance apertures beingangularly displaced in said scanning mechanism about said scanning axisto successively face said scene as said scanning mechanism rotates.

10. Apparatus as set forth in claim 9 wherein said deflection meansincludes a first reflective surface means, and means for moving saidfirst reflective surface means relative to an axis transverse to saidscanning axis after said first scanning period has been completed, toreorient said first reflective surface means during said second scanningperiod.

ll. Apparatus as set forth in'claim 10 wherein said means for movingsaid first reflective surface means includes means for causing saidfirst reflective surface means to rotate approximately 90 around saidaxis transverse to said scanning axis.

12. Apparatus as set forth in claim 10 wherein said first reflectivesurface means includes first and second reflective surfaces positionedorthogonally to each other along said axis transverse to said scanningaxis, and said means for moving said first reflective surface meansincludes means for moving said first reflective surface means along saidaxis transverse to said scanning axis, whereby either said first orsecond orthogonal reflective surface may be selectively positionedrespectively in either said first or second optical paths 13. Apparatusas set forth in claim 10 wherein:

a. said deflection means includes a second reflective surface meansspaced from said first reflective surface means along said scanningaxis, said second reflectivesurfacc means being rigidly positioned insaid scanning mechanism; and

b. said film medium is positioned in a cylindrical plane substantially360 about said scanning axis.

14. Apparatus as set forth in claim 10 wherein:

said deflection means includes a second reflective surface means spacedfrom said first reflective surface means along said scanning axis;

b. means are provided for moving said second reflective surface meansrelative to an axis transverse to the scanning axis after said firstscanning period to reorient said second reflective surface means duringsaid second scanning period; and

c. the film medium is positioned in a cylindrical plane substantially labout said scanning axis.

1. A panoramic camera having a single lens system scanning mechanism,which rotates about an axis of rotation, for providing a plurality ofscans of an area of interest during each revolution of said scanningmechanism, comprising: a. said scanning mechanism having firstdeflection means for scanning the area of interest, and first means formoving said deflection means relative to an axis transverse to the axisof rotation of said scanning mechanism after a scan has been completedduring a first portion of revolution to reorient said deflection meansto perform anotHer scan of the area of interest during another portionof that revolution; and b. said scanning mechanism further having seconddeflection means spaced from said first deflection means for rotationwith said first deflection means, and second means for moving saidsecond deflection means relative to an axis transverse to said axis ofrotation after said first deflection means has completed scanning from afirst and second angular limit and said second deflection means hasexposed a section of film between a third and a fourth angular limit, toposition said second deflection means to receive radiation from saidfirst deflection means and again direct it toward said third angularlimit.
 2. The panoramic camera of claim 1 in which said second means formoving includes shaft means parallel to said transverse axis relative towhich said second deflection means is movable, and to which said seconddeflection means is fixed, and second drive means for moving said shaftmeans.
 3. The panoramic camera of claim 2 in which said second drivemeans imparts rotational motion to said shaft means.
 4. The panoramiccamera of claim 2 in which said second drive means imparts linear motionto said shaft means.
 5. A panoramic camera having a single lens scanningmechanism for providing a plurality of scans of an area of interestduring each revolution of said scanning mechanism comprising: firstradiation reflection means for scanning an area to be photographed froma first angular limit to a second angular limit; film positioning meansfor receiving photographic film and supporting it in a cylindrical patharound the axis of rotation of said scanning mechanism; second radiationreflection means, spaced from said first reflection means and rotatablewith it, for receiving radiation from said first reflection means anddirecting it onto said film from a third to a fourth angular limit;means for moving said first reflection means relative to an axistransverse to said axis of rotation, after it has completed scanningfrom said first to said second limit, to position said first reflectionmeans to again receive radiation form the direction of said first limitand reflect it to said second reflection means; and second means formoving said second reflection means relative to an axis transverse tosaid axis of rotation, after it has completed directing radiation ontosaid film between said third and fourth limits, to again directradiation from said first reflection means toward said third limit.
 6. Apanoramic camera having a single lens system scanning mechanism, whichrotates about an axis of rotation, for providing a plurality of scans ofan area of interest during each revolution of said scanning mechanism,comprising: a. film positioning for receiving photographic film andpositioning it in a plurality of arcuate portions of a cylindrical patharound said axis of rotation; and b. said scanning means having firstdeflection means for scanning the area of interest, and first means formoving said deflection means relative to an axis transverse to the axisof rotation of said scanning mechanism after a scan has been completedduring a first portion of a revolution to reorient said first deflectionmeans to perform another scan of the area of interest during anotherportion of that revolution.
 7. A panoramic camera having a single lenssystem scanning mechanism which rotates about an axis of rotation, forproviding a plurality of scans of an area of interest during eachrevolution of said scanning mechanism, comprising: a. film positioningmeans for receiving two photographic films and positioning each of themin separate arcuate portions of a cylindrical path around said axis ofrotation; and b. said scanning mechanism having first deflection meansfor scanning the area of interest, and first means for moving saiddeflection means relative to an axis transverse to the axis of rotationof said scanning mechanism after a sCan has been completed during afirst portion of a revolution to reorient said first deflection means topreform another scan of the area of interest during another portion ofthat revolution.
 8. A panoramic camera having a single lens systemscanning mechanism, which rotates about an axis of rotation, forproviding a plurality of scans of an area of interest during eachrevolution of said scanning mechanism, comprising: said scanningmechanism having first deflection means for scanning the area ofinterest, and first means for moving said deflection means relative toan axis transverse to the axis of rotation of said scanning mechanismafter a scan has been completed during a first portion of a revolutionto reorient said first deflection means to perform another scan of thearea of interest during another portion of that revolution; and b. saidscanning mechanism further having second deflection means, including areflection element, spaced from said first deflection means for rotationwith said first deflection means.
 9. In an optical bar panoramic camerawherein an optical bar scanning mechanism with a single lens systemrotates about a scanning axis to scan a film medium, positioned in acylindrical plane about the scanning axis, with the image of aphotographed scene, the improvement comprising deflection means,including a positionable image deflector, in said scanning mechanism fordeflecting said image to the film medium by a first optical path, havinga first entrance aperture, during a first scanning period when saidfirst entrance aperture faces said scene and said image deflector is ina first position, and for deflecting said image to the film medium by asecond optical path, having a second entrance aperture, during a secondscanning period when said second entrance aperture faces said scene andsaid image deflector is in a second position, said first and secondentrance apertures being angularly displaced in said scanning mechanismabout said scanning axis to successively face said scene as saidscanning mechanism rotates.
 10. Apparatus as set forth in claim 9wherein said deflection means includes a first reflective surface means,and means for moving said first reflective surface means relative to anaxis transverse to said scanning axis after said first scanning periodhas been completed, to reorient said first reflective surface meansduring said second scanning period.
 11. Apparatus as set forth in claim10 wherein said means for moving said first reflective surface meansincludes means for causing said first reflective surface means to rotateapproximately 90* around said axis transverse to said scanning axis. 12.Apparatus as set forth in claim 10 wherein said first reflective surfacemeans includes first and second reflective surfaces positionedorthogonally to each other along said axis transverse to said scanningaxis, and said means for moving said first reflective surface meansincludes means for moving said first reflective surface means along saidaxis transverse to said scanning axis, whereby either said first orsecond orthogonal reflective surface may be selectively positionedrespectively in either said first or second optical paths.
 13. Apparatusas set forth in claim 10 wherein: a. said deflection means includes asecond reflective surface means spaced from said first reflectivesurface means along said scanning axis, said second reflective surfacemeans being rigidly positioned in said scanning mechanism; and b. saidfilm medium is positioned in a cylindrical plane substantially 360*about said scanning axis.
 14. Apparatus as set forth in claim 10wherein: said deflection means includes a second reflective surfacemeans spaced from said first reflective surface means along saidscanning axis; b. means are provided for moving said second reflectivesurface means relative to an axis transverse to the scanning axis aftersaid first scanning period to reorient said seconD reflective surfacemeans during said second scanning period; and c. the film medium ispositioned in a cylindrical plane substantially 180* about said scanningaxis.